delete all kinda stuff

delete function implemented
on pressed -> pop up => are you sure about that?
yes: all rating from all pages will be cleared
no: nothing happens, pop closes

lib/providers/essenProvider.dart

@@ -19,4 +19,11 @@ class EssenProvider extends ChangeNotifier {
     freiText = text;
     notifyListeners();
   }
+
+  void resetAllFields(){
+    freiText = "";
+    ratingGeschmack = 0;
+    ratingQuali = 0;
+    notifyListeners();
+  }
 }